Extensible mast derrick



Aug. '13, 1963 c. F. BACK EXTENSIBLE MAST DERRICK Filed April 28, 1961INVENTOR. CflEL F 5146K HIS ATTORNEYS JIG. 2

Unite States 3', 1 Patented Aug. 13, 1963 This invention relates to ahoist device and more particularly to a hydraulically controlled devicefor lifting loads from below the surface of the earth; however, thisinvention is not necessarily so limited.

In the construction of apparatus for pumping water from subterraneanwells, it has become conventional prac tice to employ pumps which areeither submerged in or supported just above the subterranean well. Insuch cases, repairs of the pumping apparatus is complicated by the needto lift the pump to the surface of the earth so as to make the pumpaccessible for repair.

Ordinarily, when the well is initially constructed, the well drillingapparatus is provided with attachments which can be used to lower thepumping apparatus into the well and, if necessary, to raise the pumpingapparatus out of the well. However, the well drilling equipment is bothmassive and expensive and, once a well is completed, it is no longereconomically feasible to return the equipment to the well for makingincidental repairs to the pumping apparatus. There is a clear need forinexpensive hoist devices which can be easily transported to the site ofa Well for making incidental repairs.

An object of the present invention is to provide a light weight hoistdevice of a type readily transported on light trucks.

Another object of the present invention is to provide an improved hoistdevice utilizing a telescopic mast and including means for extending themast, said means having a double function in that it also provides thesource of power for operating the hoist.

Another object of the present invention is to provide a hoist deviceincluding a telescopic mast and new and improved braces for supportingthe mast in an upright position.

Still another object of the present invention is to provide a hoistdevice having a telescopic mast and hydraulically actuated means forelevating the mast to an upright position.

Still another object of the present invention is to provide a hoistdevice including a telescopic mast and duofunctional hydraulic actuatormeans capable of extending the mast and also capable of powering thehoist mechanism.

Still a further object of the present invention is to provide a new andimproved tackle mechanism effective to convert a linearly directed forceto a rotational torque, said tackle mechanism including torsion meanseffective to maintain the cable of the tackle mechanism taut at alltimes.

Other objects and advantages reside in the construction of parts, thecombination thereof, the method of manufacture and the mode ofoperation, as will become more apparent from the following description.

In the drawings:

FIGURE 1 is a side elevational view illustrating the hoist mechanism ofthe present invention mounted on a truck.

FIGURE 2 is a greatly enlarged fragmentary side elevation viewillustrating two positions of the hoist mechanism.

FIGURE 3 is a fragmentary plan view taken in the direction of the arrows3--3 in FIGURE 2.

FIGURE 4 is an enlarged fragmentary perspective view illustrating blockand tackle apparatus employed in the present invention.

FIGURE 5 is an enlarged fragmentary section view taken along the line5-5 of FIGURE 2.

Referring to the drawings in greater detail, FIGURE 1 illustrates thehoist apparatus of the present invention mounted upon the bed of a truck10. The supporting frame for the hoist apparatus comprises a pair ofspaced upright posts 12 and 14' joined by transverse beam 16 bestillustrated in FIGURE 2. Struts 18 and 20 support the posts 12 and 14 ina substantially vertical position.

The support members 12, 14, 16, 18 and 20, which are visibly in thedrawings, form only one side of the supporting structure for the mast.The opposite side of the supporting structure substantially duplicatesthe side which is visible and is spaced behind the visible side from thedirection viewed in FIGURES 1 and 2. The two sides of the supportingstructure are connected in spaced relation by crossed bars not visiblein the drawings to form a rigid framework.

Pivotally mounted adjacent the upright posts 12 between the two sides ofthe supporting framework is an elongate tubular mast 22 whichtelescopically receives an extension 24. A hydraulic actuator 26 fixedlyattached to the lower portion of the mast 22 actuates a piston 28 formoving the extension 24. Secured to the outer end of the piston 28 is apulley block 30 adapted to engage an actuator rod 32 which is fixedlyattached to a bracket 34 mounted on the upper end of the extension 24.Through operation of the actuator 26, which is bi-directional, theextension 24 may be raised or lowered so as to increase or decrease theeffective length of the mast.

The mast 22 is adapted to be pivoted from the upright position shown insolid line detail in FIGURES 1 and 2 to a horizontal position shown inphantom detail in FIG- URE 2 by means of a second hydraulic actuator 36.The lower end of this actuator is secured pivotally be tween thetransverse support beams 16 while the piston 38, driven by the actuator,is attached pivotally at 44 to a flange 42 secured to the mast 22.

Braces are provided for supporting the mast in an upright position. Thebrace structure comprises an elongate brace 46 pivotally secured to theextension 24 and a telescopic brace 48 pivotally connected between thelower end of the brace 46 and the supporting framework between the posts14. As clearly shown in FIGURES 1 and 2, the two braces 35 and 48cooperate to support the mast, when upright, in a position slightlydeviated from the vertical such that the mast has a tendency to fallaway from the truck. This places the braces 46 and 48 in tension. Inorder to avoid a dead center position as would occur if the braces werealigned in a straight line, a pivot arm 62 holds the pivotal connectionbetween the braces 46 and 48 in spaced relation to the mast 22. Thiskeeps the braces 46 and 48 slightly cocked.

It is evident from inspection of FIGURES 1 and 2 that lowering of theextension 24 into the mast 22 can be accomplished only if one of thebraces 46 or 48 can be shortened. For this reason, the brace 48 isconstructed in two sections 50 and 52 which may telescope one into theother. As can be observed in FIGURE 3, the section 50 comprises twoparallel bars 50a and 50b and the section 52 comprises two parallel bars52:: and 52b. The bars of section 52 are joined at one end by a clev-isand at the other end by a transverse plate 56. The clevis 60 forms thepivotal connection between the uprights 14 of the supporting frame andthe telescopic brace. The plate 56 is provided with apertures whichslidably receive the parallel bars 50a and 50b of the section 50. Theseparallel bars are joined by a plate 54- which is also apertured toslidably receive the parallel bars 52a and 52b of the section 5-2.Through this construction, the section 52 is free to slidetelescopically into the section 50. A cross piece 58 mounted fixedlybetween the bars 52a and 52b limits the maximum extension of thetelescopic brace 48, the location of the cross piece 58 determining thedeviation of the mast 22 irom the vertical.

As illustrated in FIGURE 3, the brace 46 is constructed from parallelbar elements 4 6a and 46b pivotal- 1y joined to the bars 50a and 50b ofthe telescopic brace 48. Similarly, the pivot arm 62 is also constructedfnom parallel bar elements 62a and 62b pivotally connected to the bars50a and 50b of the telescopic brace.

With this brace construction, it is evident that movement of the mastextension 24 into the mast 22 causes the telescopic brace 48 to reducein size as the brace 46 moves downwardly to a position parallel with themast 22, the pivot arm 62 pivoting downwardly. In such position, thebraces do not interfere with pivotal movement of the mast 22 to thehorizontal position illustrated in FIG- URE 2.

In the present invention, the actuator 26, which supplies power toposition the mast extension 2 4, is also used to supply power forhoisting loads. In order to free the actuator 26 for performing thisfunction, a latch 66 is pivotally mounted on the upper portion ofthemast 22 by means of a suitable bracket 68. This latch 66 is permittedto project inwardly of the mast 22 through an aperture'70 formed in thewall of this mast. An elongate rod 72 hangs downwardly from the latch 66and the weight of this rod functions to bias the latch into the aperture70. Thus, when the extension 24 is elevated by the actuator 26 to such aposition that the lower end of the extension passes above the latch 66,the latch pivots to the interior of the mast 22. Upon subsequentretraction of the actuator 26, the latch 66 engages and supports thelower end of the extension 24 as the pulley block 30 moves out ofcontact with the actuator rod 32. To assist in this function, the latchis provided with an inclined surface 74 which moves to a substantiallyhorizontal position as the latch pivots downwardly under the weight ofthe extension 24.

The rod 72 which hangs from the latch 66 extends downwardly to aconvenient height where the operator of the hoist mechanism may graspthis rod. When it is desired to lower the extension 24, the actuator 26is raised sufiioiently to contact the actuator rod 32 and lift theextension off the latch 66; then, by raising the rod 72, the operatormay hold the latch upwardly to permit the extension to pass freely intothe mast 22 as the actuator 26 is retracted. FIGURE 2 illustrates a hook76 which may be used to hold the rod 72 loosely adjacent the mast 22. Inorder to equip the actuator 26 for hoisting a load, the pulley block 30at the upper end of the piston 23 supports two pulleys 80 and 82.Another pulley 84 is mounted at the base of the mast 22 with a bracket86-. Journalled for rotation between the two sides of the supportingframe is a drum 88 which supplies a cable 90. Also, journalled betweenthe sides of the supporting frame is a pulley 92. The cable 90 passesfrom the drum 88 under the pulley 92 over the pulley 82 in the block 30,then downwardly underthe pulley 84, then upwardly over the pulley 80 inthe block 30, and then downwardly to a fixed point of attachment 94which is located at any convenient point on the supporting frame. Withthis arrangement, four lengths of the cable 90 lead to the pulley block30. Accordingly, for each foot of upward movement of the pulley block30, four feet of cable are withdrawn from the 88. w

r In order to permit downward movement of the pulley block 30 withoutunraveling the cable 90, means are provided for tensioning the cable 90at all times. This means includes a drum 100' fixedly attached inconcentric relation to the drum 8 8, the drum 100- being considerablysmaller in diameter than the drum 88. The drum 100 supplies the cable102 which is attached to a second drum 104. The drum 104 is mountedfixedly on a shaft 106 which is supported for rotation adjacent thestrut 18 by journals 108 and 110. Encircling the shaft 106 between thesejournals is a coil spring 1112. One end of this spring, the right end asviewed in FIGURE 2, is fixedly secured to the journal .110. The otherend of this spring is fixedly secured to the shaft 106. With thisconstruction, rotation of the drum 88 to supply cable 90 causes cable102 to be drawn onto the drum 100 and thereby generates a torsionalrestoring force in the spring 112. This torsional restoring forcemaintains cable 90 taut at all times.

Since the drum 100 is considerably smaller than the drum 88, the lengthof cable 102 required to maintain the restoring torque is only afraction of the length of the cable 90 associated with the block andtackle mechanism driven by the actuator 26.

From the foregoing description, it will be apparent that upward anddownward movement of the piston 28 controlled by the actuator 26 resultsin clockwise and counterclockwise rotation of the drum 88. Thisrotational movement of the drum 68 is utilized for hoisting loads bypro- 1 viding a third drum 120' adjacent the drum 88 as shown in FIGURE4. The drum is mounted for rotation about the same axis as the drum 88but is free to rotate independently of the drum 88. Thus, when theactuator 26 is employed to raise and lower the mast extension 24, asdescribed previously, the rotational movement of the drum 88 is notnecessarily transferred to the drum 120. To transfer rotary movementfrom the drum 88 to the drum 120, a key 122 is passed through a suitableaperture in the drum 88 and into a suitably located aperture in the drum120. With the key in place the drums 88 and 120 are caused to rotate inunison.

The drum 120 supplies a hoisting cable 124 which moves upwardly to thetop of the mast extension 24 where it passes over a pulley 126 supportedin the bracket 34. From the pulley 126, the cable 124 passes downwardlyfor connection to a load 114. With the block and tackle arrangementillustrated in the drawings, upper movement of the piston 28 causes thedrum 120 to wind in the cable 124 thus hoisting the load. With downwardmovement of the piston 28, any load on the cable 124 cooperates with thespring 112 to maintain tension in the cable 90.

For operation of the actuators 26 and 36, an oil reservoir 132 isprovided on the bed of the truck 10 and a pump mechanism is mountedunder the bed, this pump mechanism being operated from a power takeoffin the transmission for the truck. FIGURE Z schematically illustartestwo operating levers 134 and 136 which regulate suitable reversingvalves, not shown, one for each of the actuators 26 and 36.

The hoistingapparatus is ordinarily transported on the truck ldwhen themast 22 is in the horizontal position illustrated in FIGURE 2. When thehoist apparatus is to be placed into operation, the transmission for thetruck is shifted to operate the pump 130*. The lever 134 is thenactuated to cause the actuator 36 to pivot the mast to its uprightposition. Thereafter lever 136 is actuated to cause the actuator 26 tomove the extension 24 upwardly above the latch 66. Thereafter the lever136 is pivoted oppositely to retract the actuator 26 permitting thelatch 66 to engage and support the extension 24. Throughout theproceeding operations, the key 122 is removed so that rotaton of thedrum 8% is not transferred to the drum 120. After the actuator 26 hasbeen lowered, the key 122 is inserted to lock the drum 120to the drum38. For easy insertion of the key 122, a number of spaced key engagingapertures may be provided in the drum 120.

After the key '122 has been inserted into place, the actuator 26 may beused as required for hoisting operations.

When the work to done is completed, the key 122 is removed to disengagethe drum 120 and the actuator 26 is elevated to raise the extension 24off the latch 66. Then the rod 72 is pushed upwardly manually to permitfree movement of the extension 24 into the mast 22 and the actuator 2.6is lowered. Finally, the lever 13 i is moved to lower the mast 2 2 toits horizontal position.

From the foregoing, it is apparent that the entire operation of thepresent hoist mechanism is automatic with the exception of manualmanipulation of the key 122 and manual manipulation of the rod 72.

While the present hoist mechanism has been illustrated and described asmounted on a truck for mobility, it is to be understood that theapparatus is fully applicable to stationary mountings. Further, it is tobe understood that the hoisting apparatus may be mounted on other typesof vehicles.

While the apparatus of the present invention has been described asutilizing hydraulic actuator devices, it is deemed within the purview ofthe present invention to utilize other types of linear actuator devices.It is also eerned within the purview of the present invention to utilizeother types of tension devices for maintaining tenison in the block andtackle mechanism.

Although the preferred embodiment of the device has been described, itwill be understood that within the purview of this invention variouschanges may be made in the form, details, proportion and arrangement ofparts, the combination thereof and mode of operation, which generallystated consist in a device capable of carrying out the objects setforth, as disclosed and defined in the appended claims.

Having thus described my invention, I claim:

1. A hoist apparatus comprising a telescopic mast having an upper and alower section, means to support said mast in an upright position, alinear actuator device mounted on said lower section and engageable withsaid upper section to elevate said upper section, means to latch saidupper section in an elevated position, said actuator device beingthereby free to operate independently, a pulley supported on said uppersection, a cable drum fixedly attached with respect to said supportmeans, cable means Wrapped on said drum and passing over said pulley forengaging a load, and means responsive to said actuator device to rotatesaid drum.

2. A hoist apparatus comprising, in combination, a cable drum, a pulley,mast means supporting said cable drum and pulley in spaced relation,said drum supplying a cable which passes over said pulley to engage aload, and means to rotate said cable drum to hoist the load, said meanscomprising a reciprocally operable linear actuator device supported bysaid :mast means, a second drum secured to said cable drum for unitarymovement therewith, block and tackle means responsive to linear movementof said actuator device and including a cable for rotating said seconddrum to thereby hoist the load, and tensioning means applying a torqueto said second drum opposing rotation thereof when said linear actuatordevice is driven in one direction, said tensioning device 'holding saidsecond cable means taut during operation of said actuator device in thereverse direction.

3. A hoist apparatus comprising a telescopic mast having an upper and alower section, means to support said mast in an upright position, alinear actuator device mounted on said lower section and engageable withsaid upper section to elevate said upper section, means to latch saidupper section in an elevated position, said actuator device beingthereby free to operate independently, a pulley supported on said uppersection, a cable drum fixedly mounted with respect to said supportmeans, cable means wrapped on said drum and passing over said pulley forengaging the load, and means responsive to said actuator device torotate said drum, said last named means including a second drum securedto said cable drum 'for unitary rotation therewith, block and tacklemeans responsive to upward movement of said linear actuator device forrotating said second drum and thereby rotating said cable drum, andtensioning means supplying a torque to said second drum to maintain saidblock and tackle means taut.

4. The hoist apparatus according to claim 3 including means to detachsaid cable drum from said second drum so as to enable operation of saidlinear actuator device independently of said cable drum.

References Qited in the file of this patent UNITED STATES PATENTS963,237 Milton July 5, 1910 1,632,935 Turner et a1 June 21, 19271,793,381 Vanatta et a1 Feb. 17, 1931 1,975,555 Presley Oct. 2, 19342,495,392 Smith Jan. 24, 1950 2,588,037 Orton Mar. 4, 1952 2,670,177Pearson Feb. 23, 1954 2,706,022 Brown Apr. 12, 1955 2,848,977 Prestrudet al Aug. 26, 1958

1. A HOIST APPARATUS COMPRISING A TELESCOPIC MAST HAVING AN UPPER AND ALOWER SECTION, MEANS TO SUPPORT SAID MAST IN AN UPRIGHT POSITION, ALINEAR ACTUATOR DEVICE MOUNTED ON SAID LOWER SECTION AND ENGAGEABLE WITHSAID UPPER SECTION TO ELEVATE SAID UPPER SECTION, MEANS TO LATCH SAIDUPPER SECTION IN AN ELEVATED POSITION, SAID ACTUATOR DEVICE BEINGTHEREBY FREE TO OPERATE INDEPENDENTLY, A PULLEY SUPPORTED ON SAID UPPERSECTION, A CABLE DRUM FIXEDLY ATTACHED WITH RESPECT TO SAID SUPPORTMEANS, CABLE MEANS WRAPPED ON SAID DRUM AND PASSING OVER SAID PULLEY FORENGAGING A LOAD, AND MEANS RESPONSIVE TO SAID ACTUATOR DEVICE TO ROTATESAID DRUM.